1. Field of the Invention
The invention relates to a semiconductor light emitting device and a method for manufacturing the same.
2. Background Art
To improve the light extraction efficiency of a semiconductor light emitting device such as an LED (Light Emitting Diode), it is desirable to use a material having a high reflectance as an electrode. Although silver and silver alloy have high reflecting characteristics even with respect to light emitted with short wavelengths of 400 nm or less and have good electrical characteristics such as ohmic characteristics and contact resistance, problems such as migration and chemical reactions easily occur and the adhesion is unfortunately poor.
In the case where sintering, for example, is performed to improve the adhesion, the reflecting characteristics easily deteriorate. Although configurations may be considered in which a metal layer is formed to cover a silver electrode after the silver electrode is formed, migration and chemical reactions occur in the silver electrode partway through processes of conventional methods; and the characteristics deteriorate. Even in the case where sintering is performed simultaneously on a protective film formed by a continuous film formation after the silver formation to protect the surface of the silver, the adhesion easily deteriorates in low temperature sintering; and the reflecting characteristics easily deteriorate in high temperature sintering.
Although JP-A 2009-49266 (Kokai) discusses a configuration to suppress the migration and chemical reactions of silver by providing, for example, a second metal film of Pt/Au excluding silver on a first metal film of silver or silver alloy, there is room for improvement to achieve better reflectance, electrical characteristics, stability, and adhesion.